While the Kindle and Nook are busy adding HD displays and more storage, at least one company is focusing on making eReaders as portable as possible. German developer, txtr, recently revealed the Beagle, which it claims is the smallest eReader in the world, with a 5-inch screen and a weight of 128 grams (about 4.5 ounces).

The Beagle's most noticeable feature is of course it's miniscule size. Except for the battery case, the whole device is less than 5 mm thick and has an overall volume of only 100 cubic centimeters, meaning it can fit in your pocket just as easily as a smartphone. Its face has buttons for navigation and a crisp 5-inch E-ink display, which gives 8 levels of grayscale and an 800 x 600 resolution. Users will only be able to read comfortably with a few paragraphs on the screen at a time, but that's to be expected with the smaller screen. Readers will also have a choice of four different colors: jade green, grapefruit, purple, and turquoise.

Unfortunately, the Beagle's small size also means it lacks many of the features found in most of its larger competitors. For starters, it has no touchscreen, no backlight, no additional programs aside from the eBook reader, and not even a standby mode – it can only turn completely on or off.

Most glaring of all though, it has no Wi-Fi support. All eBooks are downloaded through Bluetooth from an Android device using the txtr app (an iOS version is reportedly in the works). The font size and text orientation are also rendered in the app itself and cannot be changed once a document has been uploaded to the Beagle. Even after all that though, it's 4 GB memory can only store up to five eBooks at a time, so it might not be suited for especially long trips on its own.

The Beagle is also powered by two AAA batteries, which the developer claims will last one year or 12-15 books before needing to be changed. The upside of no inbuilt rechargeable battery being no need for yet another charging cable for a mobile device.

But the loss of features may be worth it when compared to the Beagle's next best feature: its price. Txtr has stated its eReader could be sold as part of a mobile service contract for as low as €9.90 (about US$13), making it more of an accessory to a smartphone than a standalone device. The company hopes that in this way it can reach customers who have not yet begun using digital reading services.

It will be interesting to see how successful textr's stripped-down eReader will fare if it reaches stores. There could be quite a few people out there who aren't interested in the pricier Kindles or Nooks but might jump at the chance for an eReader that costs about as much as an average paperback. Txtr is currently in talks with several mobile carriers in Europe, Asia, and the U.S. about bringing the Beagle to retailers. In the meantime, the company is preparing to sell the eReader through it's online book stores in the near future.

Check out the video below to see some of the Beagle's features in use.